Here are my top 10 reasons for opposing torture:
1. It's illegal. If you want to legalize it, legalize it, but don't discard the whole idea of following laws.
2. When the United States tortures, it loses the ability to tell any other nation not to torture, including nations you wouldn't want torturing the people you wouldn't want tortured, namely Americans.
4. False statements created by torture were used to take this nation into a war in Iraq that has killed over a million Iraqis and thousands of Americans at enormous cost in dollars and in safety and prospects for peace. One justification for that war was to stop Iraqi torture, but Iraq now tortures and America can say nothing against it.
5. Torture was used even after the invasion to generate more false statements purely for political purposes.
7. Expert interrogators do not use torture because it does not work as quickly or as reliably as other methods. So torturing someone to save your kidnapped child would be less likely to save your kidnapped child than relying on a skilled interrogator.
8. Torturing people brutalizes the torturers as well, damaging them and those they live with.
9. Torturing damages our society, brutalizing the thoughts and practices of prison guards, police, and citizens.
10. The myth that certain people cannot be spoken to and must be tortured creates deeply damaging prejudices, because those people are always defined as part of a certain racial, religious, or cultural group that comes to be seen as sub-human.
I hope this clears up the confusion.